Btrfs: Fix hole insertion corner cases
There were a few places that could cause duplicate extent insertion,
this adjusts the code that creates holes to avoid it.
lookup_extent_map is changed to correctly return all of the extents in a
range, even when there are none matching at the start of the range.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 51fc06d..6700548 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -133,6 +133,7 @@
ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
start, ins.objectid, ins.offset,
ins.offset);
+ btrfs_check_file(root, inode);
num_bytes -= cur_alloc_size;
alloc_hint = ins.objectid + ins.offset;
start += cur_alloc_size;
@@ -965,12 +966,18 @@
u64 mask = root->sectorsize - 1;
u64 pos = (inode->i_size + mask) & ~mask;
u64 block_end = attr->ia_size | mask;
+ u64 hole_start;
u64 hole_size;
u64 alloc_hint = 0;
if (attr->ia_size <= pos)
goto out;
+ if (pos != inode->i_size)
+ hole_start = pos + root->sectorsize;
+ else
+ hole_start = pos;
+
mutex_lock(&root->fs_info->fs_mutex);
err = btrfs_check_free_space(root, 1, 0);
mutex_unlock(&root->fs_info->fs_mutex);
@@ -980,19 +987,21 @@
btrfs_truncate_page(inode->i_mapping, inode->i_size);
lock_extent(em_tree, pos, block_end, GFP_NOFS);
- hole_size = (attr->ia_size - pos + mask) & ~mask;
+ hole_size = block_end - hole_start;
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
err = btrfs_drop_extents(trans, root, inode,
- pos, pos + hole_size, pos,
+ pos, block_end, pos,
&alloc_hint);
if (alloc_hint != EXTENT_MAP_INLINE) {
err = btrfs_insert_file_extent(trans, root,
inode->i_ino,
- pos, 0, 0, hole_size);
+ hole_start, 0, 0,
+ hole_size);
+ btrfs_check_file(root, inode);
}
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);